This invention relates generally to apparatus and method for intimately contacting an effluent gas flow with a treating liquid such as water whereby fine particulate solids carried in the gas flow are transferred to the liquid flow prior to further treatment of the gas or its exhaustion into the atmosphere. More particularly, the invention pertains both to the structural design and the use of a gas and liquid contacting chamber that may comprise a part of a gas effluent processing system.
It is a known practice to utilize a contacting chamber, often referred to as a dust collector, to subject a particle-laden gas flow to a liquid flow by centrifugally whirling the gas flow to insure thorough intermixing with the liquid flow and thereby cleanse the gas of the particulate solids carried therein. Once the transfer action has been completed within the chamber whereby the particulate matter is picked up by liquid droplets, the cleaned gas and the liquid are discharged as separate flows from the chamber. Where the aforementioned method is carried out through the use of a cylindrical casing defining the contacting chamber and the liquid and gas are introduced to the chamber to move generally concurrently therethrough from the upper end toward the lower, it is a known practice to have the lower end wall of the cylindrical casing converge to a funnel-like discharge outlet for the liquid, and to have a substantially large gas outlet in the form of a cylindrical duct of smaller diameter than the chamber disposed concentrically within the chamber's lower end and projecting outwardly therefrom to exhaust the gas flow from the chamber. The arrangement heretofore described is to enable the liquid, which progresses downwardly through the chamber along the inner sidewall surface thereof because of the centrifugal forces of the whirling gas flow, to be channeled by the casing's converging lower end to a relatively small liquid outlet conduit. Two examples of a lower end arrangement for such a chamber are shown in a Czechoslovakian Pat. No. 96056. FIG. 1 thereof discloses a contacting chamber having an oblique bottom wall for directing liquid flow to a discharge conduit and a large tubular duct for exhausting gas from the chamber. The patent also has a FIG. 4 showing a pair of gas ducts each projecting through inwardly converging surfaces, with the latter surfaces meant to guide liquid flow to a common axially aligned outlet conduit.
Several problems have been recognized in the construction and use of collecting chambers or separators of the aforementioned types. In the lower end of such a chamber, the circumferential force of the centrifugal gas whirl acts upon the liquid flow and tends to prevent it from following the desired course established by the converging or oblique lower end of the chamber. This inhibiting of the liquid flow effectively retards it from direct rapid entry to the outlet conduit such that particulate solids are lost from the water flow. These solids then tend to build up on the converging surface of the chamber's lower end. Moreover, the described prior art arrangements for a collecting chamber lower end often constitute a substantially large and bulky portion representing high material and manufacturing costs not commensurate with its relatively poor functional efficiency.